Slave system and method



A. M. FUCHS SLAVE SYSTEM AND METHOD March 12, 1963 4 SheetsSheet 1 Filed April 24, 1952 INVENTOR. 4MAHAM was March 12, 1963 A. M. FUCHS- SLAVE SYSTEM AND METHOD 4 Sheets-Sheet 3 Filed April 24, 1952 INVENTOR. 4mm HAM/l1. fVChJ Arroklvzv 3,081,949 SLAVE SYSTEM AND METHOD Abraham M. Fuchs,'New York, N.Y., assignor to The endix Corporation, a corporation of Delaware Filed Apr. 24, 1952, Ser. No. 284,094 (Ilaims. (Cl. 244-14) This invention relates to a system for, and method of, positioning a missile antenna and more particularly to a system for properly positioning the antenna of a missile before the missile is launchedso that the missile will have as good a chance as possible of intercepting a target.

In co-pending application Serial No. 175,442, filed July 22, 195 0, by Edmund F. Lapham, J r. and Ian H. McLaren, now abandoned, a system is disclosed for guiding a missile to intercept a target. The system for guiding the missile is an active one, in that it operates in the missile independently of any equipment in the interceptor aircraft from which it is launched. The system operates to guide the missile on a collision course towards a target, such that the missile gradually overtakes the target along a line of sight between the missile and the target but merely follows the movement of the target in the directions perpendicular to the line of sight.

To maintain the missile on the collision course, the missile is pivotable relative to its antenna in three substantially perpendicular planes. In case the missile deviates from its proper course, the missile is pivoted relative to its antenna in one or the other of the three substantially perpendicular planes so as to return the missile to its proper course and to maintain the antenna pointed at the target. However, the missile has only a limited movement in a predetermined one of the three plan-es. Because of its limited movement in the predetermined plane, the missile is pivoted in a compensatory manner relative to its antenna in the other two planes to provide a substitution for the movement in the predetermined plane.

In order for the missile to have as good a chance as possible of intercepting the target, especially when the target is moving, the missile should be launched under optimum conditions. One of the most important conditions is that the missile antenna should be pointed at the target before it is launched. To accomplish this, the

missile antenna is electrically connected to a master antenna in the interceptor aircraft. The master antenna in the interceptor is operated by a radar system which causes the antenna to point at the target, and the missile antenna is adapted to follow the interceptor antenna.

This invention provides a system for converting the movements of .the master antenna in the interceptor aircraft into corresponding movements of the missile antenna before the missile is launched. Such a conversion is necessary because of the compensatory movements required of the antenna in certain planes to limit the movevrnent of the antenna in the predetermined plane disclosed above and to maintain the antenna pointed at the target during flight. The system operates to maintain the missile antenna pointed at the target even though the compensatory movements of the antenna to limit its movement in the predetermined plane produce a constant shift in the reference axes between the missile antenna and the interceptor antenna.

An object of this invention is to provide a system for maintaining a missile antenna pointed at a target before the missile is launched.

Another object is to provide a system of the above character for properly positioning a missile antenna before the missile is launched so that the missile will follow the best possible course to intercept a target after being launched.

3,0815%? Patented Mar. 12, 1963 A further object is to provide a system of the above character for converting the movements of a master antenna in an interceptor into corresponding movements of the missile antenna about different axes, so that the missile antenna will follow the master antenna in pointing at the target before the missile is launched.

Still another object is to provide a system of the above .character for operating in conjunction with a missile antenna before the missile is launched to limit the relative movement between the missile and the antenna in a predetermined plane by providing compensatory movementsof the antenna in other planes.

Other objects and advantages will be apparent from a detailed description of the invention and from --the.appended drawings and claims.

In the drawings:

FIGURE 1 is a perspective view of an interceptor and a missile adapted to be supported by, and launched from, the interceptor;

FIGURE 2 is an enlarged perspective view illustrating an antenna forming a part of the missile shown in FIG URE 1;

FIGURE 3 is a simplified block diagram of an electrical system for guiding the missile shown in FIGURE 1 on an optimum course towards a distant target;

FIGURE 4 illustrates the pattern of the signals refiected from the target to the missile antenna when the missile deviates duringfiight from its optimum course towards a target;

FIGURE 5 shows curves illustrating the manner in which the signals shown in FIGURE 4 are utilized by the electrical system of FIGURE 3 to correct any deviations of the missile from its optimum course towards a target;

FIGURE 6 is an enlarged rear elevational View of the missile tail fins, showing the angle through which the missile may be rotated at any instant relative to its antenna to correct any deviations in its flight;

FIGURE 7 is a view illustrating in schematic form the beam radiated towards the target by the missile antenna shown in FIGURE 2;

FIGURE 8 is a schematic diagram illustrating the relative flight paths at any instant of the missile and target after the missile has been launched;

FIGURE 9 illustrates the course adopted by the missile to intercept the target for a particular flight path of the target;

FIGURE 10 is a simplified block diagram of an electrical system for maintaining the missile antenna pointed at a target before the missile is launched; and

.FIGURE 11 is a spatial diagram schematically illustrating the manner in which the missile antenna is rotated, befo-re being launched, in accordance with the movements of a master antenna which is housed in the interceptor.

In one embodiment of the invention, a missile, generally indicated at 10 (FIGUREI), is adapted to be supported by aninterceptor, generally indicated at 12, andto overtake a target, generally indicated at 14 (FIG- URE 8), after being launched. The missile has an an: tenna, generally indicated at 16 (FIGURES 1 and 2), the movement of which is determined before the missile launching byan antenna in a radar system 20 (FIGURE 10); as will be disclosed in detail hereafter. The radar system Zilforms part of the permanent equipment of the interceptor 12. One radar system which may be used has been given the engineering designation of AN/APQ- 35. The construction and ope-ration of the AN/APQ-35 radar system are fully disclosed in Handbook of Maintenance Instructions for Radar Sets AN/APQ-35 and AN/APQ 35A (three volumes) published in 1950 under the authority of theSecretary of the Air Force and the Chief of sthe Bureau of Aeronautici .All of the compo nents shown in FIGURES 3 and are separated from the radar system so as not to form a part of the system.

In addition to the antenna 16, which is positioned at its forward end, the missile has at an intermediate position an electrical system, parts of which are shown in FIGURES 3 and 10, and also has an explosive charge at its rear end. A first pair of diametrically disposed, outwardly extending fins 24 (FIGURES land 6) is positioned at an intermediate position in the missile 10 and is adapted to be pivoted relative to the missile to alter the course of the missile in one direction. A second pair of diametrically disposed fins 26 is positioned at an intermediate position in the missile in quadrant relationship to the fins 24 and in pivotal relationship to the missile to alter the course of the missile in a direction substantially perpendicular to that con-trolled by the fins 24.

The construction and operation of the antenna 16 is disclosed in detail in co-pending application Serial No.

a socket the rotor of a synchro 38, the stator of which is supported by one of the sta-nchions.

A segment 40 of a ring gear extends from the periphery of the ring gimbal and, before the release of the missile, meshes with a gear train which includes a pinion gear 42 driven by a suitable motor. A solenoid 44 controls the position of the pinion gear 42 and, when energized, actuates its armature to move the pinion gear out of mesh with the ring gear 40.

The horseshoe gimbal 32 is suitably mounted on the ring gimbal 30 in pivotable relationship to the ring gimbal and is adapted to carry the rotor of a synchro 48, the stator of which is mounted in a socket of the ring gear. The synchro 48 is electrically connected to the motor 34 so as to operate the motor during the missile flight when an error signal is produced in it as a result of a pivotable movement of the missile relative to the horseshoe gimbal 32.

A shaft 50 is supported by the horseshoe gimbal 32 at its inner end, and a wave guide 52 is in turn suitably secured to the outer end of the shaft in aligned relationship with the shaft. The stators of a motor 54 and of an alternator 56 are mounted on the shaft and the rotors of the motor 54 and the alternator 56 are suitably secured to a retainer 58 adapted to rotate on bearings relative to the shaft 50. An annular reflector 60 having a parabolic shape in axial cross-section is suitably secured to the retainer 58, with its axis tilted in slightly skewed relationship to the shaft 50. The retainer 58, the alternator 56 and the reflector 60 are driven by the motor 54 at a substantially constant speed. Since the reflector 60 is driven at relatively high speeds and is mounted on gimbals and since it has a moment of inertia, it becomes a free gyro.

The antenna 16 as well as its alternator 56 are included in the system shown in FIGURE 3. Signals having a relatively high frequency are introduced to the antenna from a magnetron 62 when the magnetron is triggered by pulses produced at a relatively low repetition rate by a modulator 64. A range gate circuit 66 also has signals applied to it from an output terminal of the modulator 64 as well as from an output terminal of a receiver 68. Connections are made from an output terminal of the range gate circuit 66 and the output terminal of the magnetron 62 to input terminals of the receiver 68.

Two output signals having a 90 phase relationship to each other are produced by the alternator 56, as will be disclosed in detail hereafter. One of the quadrature signals is introduced to a transformer 70, which produces a pair of signals having a 180 phase relationship.- Similarly, a transformer 72 converts the other quadrature signal from the alternator 56 into a pair of signals having a 180 phase relationship to each other. The output terminals of the transformers 70 and 72 are connected to input terminals of gated amplifiers 74 and 76 and gated amplifiers 78 and 8t), respectively. Input terminals of the amplifiers 74, 76, 78 and 80 are also connected to an output terminal of the receiver 68.

The output signals from the amplifiers 74, 76, 78 and 80 are introduced to detectors 82, 84, 86 and 88, respectively, which are paired so that a signal resolver 90 receives the output of the detectors 8-2 and 84 and a signal resolver 92 receives signals from the detectors 86 and 88. As disclosed in co-pending application Serial No. 175,442 filed July 22, 1950, by Edmund F. Lapham, Jr. and Ian H. McLaren and now abandoned, the resolvers 9t) and 92 may be square card sine potentiometers having variably positioned taps connected to the mount gimbal 28 to provide an angular correction for the rotation of the missile 10 relative to the mount gimbal. A differentiator 94 and a servomechanism 96 are connected in cascade arrangement to the output terminal of the signal resolver 90, and a diiferentiator 98 and a servomechanism 100 are similarly connected to the signal resolver 92. The output terminals of the signal resolvers 90 and 92 may also be directly connected to the input terminals of the servomechanisms 96 and 100, respectively, as indicated by the broken lines in FIG- URE 3.

Before the release of the missile, the antenna in the interceptor 12 is operated by the radar system 20 (FIG URE 10) so that it points continuously at the target. The antenna pivots in a plane of azimuth, corresponding to a right or left movement in a horizontal direction, and in a plane of elevation, corresponding to an up or down movement. The movement of the inter ceptor antenna in the azimuth or elevation planes is converted by the system shown in FIGURE 10 into appropriate movements of the missile antenna 16 in the planes of the mount gimbal 28 and ring gimbal 30, as Will be described in detail hereinafter. Such movements of the antenna 16 cause it to continuously point at the target before the missile is released.

Upon the release of the missile, the solenoid 44 (FIG- URE 2) is energized to disengage the pinion gear 42 from the ring gear 40. This causes the antenna 16 to be released for free pivotal movement relative to the missile in the planes of the ring gear 30 and horseshoe gimbal 32. As the missile travels towards the target 14, the modulator 64 triggers the magnetron 62 at a "predetermined rate and causes the magnetron to pro duce pulses of energy which are transmitted towards the target by the antenna 16. Since the reflector 60 (FIG- URE 2) is slightly skewed with respect to the shaft 50 and the wave guide 52 and since the reflector is spun is indicated at 106 in FIGURE 7.

If the missile is proceeding on a proper course towards the target, the target appears on the axis 106 of the composite cone 102. This causes the strength of each transmitted pulse of energy which falls on the target to be substantailly constant and the strength of the pulses reflected from the target back to the antenna 16 to remain substantially constant. When the missile deviates from its proper course, however, the target no longer appears on the axis 106, and the strength of the beam falling on the target varies sinusoidally as the beam ro tates through a complete revolution. The phase and amplitude of the sinusoidal signal are determined'by URE 4 is produced by the reflected pulses when the target is at a position 118 in FIGURE 7 relative to the conical axis 186, and a sinusoidal envelope 112 is produced by the reflected pulses with the target in a position 114. As will be seen, the envelope 112 has a greater amplitude and a different phase than the envelope 108.

The pulses reflected by the target 14 are received by the antenna 16 and are introduced through the receiver 68 (FIGURE 3) to the gated amplifiers 74, 76, 78 and '89. Only the pulses from the target 14 are introduced to the gated amplifiers as a result of the action of the range gate circuit 66, which opens the receiver for the passage of pulses only at the time that the pulses are expected from the target. The pulses introduced to the gated amplifiers are mixed in the amplifiers with the signals from the transformers 78 and 72. As previously disclosed, each of the transformers produces a pair of signals having a phase relationship of substantially 180 to each other and a phase relationship of substantially 90 to the signals from the other transformer. The phase relationships of the signals introduced to the amplifiers 74, '76, 78 and 89 from the transformers 79 and 72 are illustrated by the envelopes 116, 118, 120 and 122, respectively, in FIGURE 5.

The pulses reflected by the target 14 to the antenna 16 pass through each of the amplifiers 74, 76, 78 and 88 (FIGURE 3) during substantially only half of the time, corresponding to the positive portion of each of the signals 116, 118, 121 and 122, respectively. The amplitude of the pulses passing through each amplifier at any instant is determined not only by the strength of the the pulse as it is introduced to the amplifier but also by the amplitude at that instant of the sinusoidal signal introduced to the amplifier from either the transformer 7t? or the transformer 72. The peak amplitude of the pulses passing through each of the amplifiers 74, 76, 78 and 89 is determined by the detector 82, 84, 86 and 88, respectively.

The signal resolver 90 operates on the signals passing through the detectors 82 and 84 to produce a resultant signal having a phase and amplitude which control the movement of the missile in the horizontal direction. The signal resolver 98 also shifts the phase of the resultant signal through an angle equal to the angle through which the missile has previously pivoted relative to the mount gimbal 28, as will be disclosed in detail hereafter. Such a phase shift is necessary because the rotation of the missile relative to the mount gimbal 28 causes the coordinates determined by the transformers 78 and 72 to become different from the coordinates represented by the fins 24 and 25. The angle through which the missile rotates at any instant relative to the mount gimbal 28 is illustrated in FIGURE 6 by the angular distance between each of the fins 24 and 25 in its solid and broken lines.

After being shifted in phase, the signal passing through the resolver 9-1 is differentiated by the difierentiator 94, and this ditlerentiated signal is either introduced directly to the servomechanism 96 or is combined with the phaseshifted signal from the resolver before being intro duced to the servomechanism. A differentiated signal is produce to indicate the rate at which any deviaticns are being corrected and to prevent hunting as the deviation approaches zero. Upon the introduction of the differentiated signal to the servomechanism 96, the servornechanism produces a pivotal movement of the fins 24. The pivotal movement of the fins in turn causes the missile to pivot relative to the ring gim'bal 38, such that the missile returns to an optimum flight path relative to the target. When the missile returns to an op timum flight path relative to the target, the antenna 16 once again points directly at the target.

It should be appreciated that the fins 24 cause. the

missileto pivot aboutthecenter; of gravity of. the miss sile even though the antenna 16 is not located at the center of gravity. However, the antenna 16 continues to point in substantially the samev direction since it opera-tes as a gyro. Only drifts, in the; gyro cause the reflector 60 to deviatefrom the line of sight between it and the target.

In like manner, the signal resolver 92 operates on the signals passing through the detectors 86 and 88 to produce a resultant signal which. controls the pivotal movement of the missile on the horseshoe gimbal 32. The phase of the signal is shifted by the resolver 92 through an angle, correspondingv to the prior rotation of the missile on the mount gimbal 28, and this phaseshifted signal is differentiated and introduced; after differentiation to the ser-vomechanism 100. The servo,- mechanism pivots the fins 26 which in turn cause the missile to pivot relative to they-horseshoe gimbal 32.

Upon a pivotal movement of the missile, relative to the horseshoe gimbal 32, a signal is produced in the synchro 48 and is introduced to the motor 34. The motor 34 then produces a relative motion between the missile 10 and the mount gimbal 28 until the signal from the synchro 48 is reduced to zero. At the same time, the missile pivot in a compensatory manner relative tothe ring gimbal 30. This compensatory motion of the missile relative to the ring gimbal occurs because of the freedom of movement provided between the missile and the ring gear when the pinion gear 42 becomes disengaged from the ringgear 40 upon the release cf the missile. Compensatory movements of-the missile in the two substantially perpendicular planesrepresented by the mount gimbal 28 and the ringgear 38 provide a substitute for the movement of the missile in a third plane substantially perpendicular to the first twoplanes, this third plane being represented by the horseshoe gimbal 32. The compensatory movements of the missilerelative to the mount gimbal 28 and the ring. gimbal 30 in .limiting the movement of the missile relative to the horse.-

shoe gimbal 32 are fully dis-closed in co-pending Serial No. 188,943 filed October 7, 1950, by Edmund F. Lapham, Jr.

The operation of the antenna 16 and the associated electrical system shown in FIGURE 3 causes the missile to follow a collision or other optimum course in which the missile gradually overtakes and finally intercepts the target. As may be seen in FIGURE 8, the missile 10 has at any instant a velocity V and the target 14 a velocity V The velocity V may be resolved into components V VM(2) and V of a coordinate system in which V is the component of velocity in the direction of a lineof sight 3.26 between the missile and the-target and 1:4(2) and Vlvm) are the components of velocity in directions substantially perpendicular to the line of sight.

Similarly the velocity V may be resolved into components V V and V along axes corresponding to the above coordinates. In an ideal collision course,

but most of the system is adapted to be retained within the interceptor for use with more than one missile.

'1fhe part, of the system housed the missile. is indicated at 300 and the part of the system housed in the interceptor is indicated at 302. The system includes the motor 54, the alternator 56 and a signal resolver 130 similar to the resolvers 90 and 92. Signals from the alternator 56 are introduced to the resolver 130 and to amplifiers 132 and 134 for isolating the alternator from subsequent stages.

Connections are made from the output terminals of the amplifiers 132 and 134 to the input terminals of an azimuth tangent potentiometer 136 and an elevation tan gent potentiometer 138, the output terminals of which are in turn connected to a summing circuit 140. The Potentiometers 136 and 138 are ganged to the antenna in the radar system 20, as disclosed by the broken lines in FIGURE 10. The output terminal of the summing circuit 140 is connected to a saturation amplifier 142, which has its output signals introduced to an input terminal of a phase sensitive detector 144. The detector 144 also has input terminals connected to an isolation amplifier 146, which receives signals on it input side from the roll resolver 130. The output terminal of the detector 144 is connected in cascade arrangement with a ditferentiator 148, a relay circuit 150 and with the motor 34, also shown in FIGURE 2. The motor operates through a gear train, indicated in block form at 163, to drive the resolver 130 and the mount gimbal 28, which is shown in block form in FIGURE for convenience.

In addition to being introduced to the amplifier 142, the output from the summing circuit 140 is applied to an input terminal of a subtracting circuit 154. An error amplifier 156,.a detector 158, a power amplifier 160 and a motor 162 are connected in cascade arangement to an output terminal of the subtracting circuit 154. The motor 162 drives a tangent potentiometer 164 when it receives a signal from the amplifier 160, the potentiometer being driven in a direction to cancel the amplifier signal. The potentiometer 164 receives an input signal from an isolation amplifier 166, the input terminal of which is connected to an output terminal of the roll resolver 130. The output from the potentiometer 164 is introduced to an input terminal of the subtracting circuit 154.

A synchro 168 housed in the interceptor is also driven by the motor 162. The output from the synchro is introduced to input terminals of a subtracting circuit 170 and a detector 172, and an error amplifier 174 is connected between the output terminal of the subtracting circuit 170 and an input terminal of the detector 172. The subtracting circuit'170 also has an input terminal which is connected to an output terminal of the synchro 38 in the missile, the rotor of which is adapted to be driven by a motor 178 through a gear train 180 and the ring gimbal 30 in the missile. The gear train 180 includes the gear segment 40 and the pinion gear 42 shown in FIGURE 2. A relay circuit 182 is connected between the output terminal of the detector 172 and the input to the left to correct any errors in azimuth; The pivotal movement of the antenna in the plane of elevation is indicated by the angle E in FIGURE 11 and in the plane .of-azimuth by the angle A.

The movements of the missile antenna 16 corresponding to those of the interceptor antenna in the planes of azimuth and elevation would normally be on'the ring gimbal 30 and the horseshoe gimbal 32. As previously disclosed, the horseshoegimbal 32 can make only a limited movement before it strikes the ring gimbal 30. Furthermore, the horseshoe gimbal is locked against move- 8 ment before the missile is released, since the pinion gear 42 is in mesh with the ring gear 40. Therefore, the antenna 16 is maintained pointed at the target by movements on the mount gimbal 28 and the ring gimbal 30.

In order to train the antenna 16 on the target 14 in accordance with the movements of the antenna in the interceptor 12, it is necessary to convert the movement of the antenna 16 in the azimuth and elevational planes into corresponding movements of the antenna 16 on the ring and mount gimbals. To obtain this conversion, the following relationships are used:

L=R tan E, (1) where L=the vertical distance between the missile 10 and th 7 target 14 at any instant; R=the horizontal distance at that instant between the missile and the plane formed by the lines of elevation and azimuth which pass through the target; and E=the angle through which the antenna in the interceptor 12 has moved at any instant in the direction of elevation; Similarly,

M =R tan A (2) where M=the horizontal distance at any instant, in the direction of azimuth, between the missile 10 and the target 14; and

A=the angle through which the antenna in the interceptor 12 has moved at any instant in the direction of azimuth.

And,

N =R tan 7 (3) where N =the total distance between the missile and the target in the same plane as the distances L and M; and 'y=the angle which the missile forms with the target when the horizontal line R serves as the base of a triangle.

But the distances L and M actually comprise the legs of a right triangle with N as the hypotenuse. Therefore,

where a=the angle between the hypotenuse N and the leg L.

Substituting Equations 1 and 2 in Equation 4,

R tan A tan A tan R tan E tan E (5) Since N is the hypotenuse of a right triangle with M and where 1' indicates a vectorial addition of tan A and tan E. If two signals proportional to tan A and to tan E are respectively produced and if these signals are vectorially combined, the phase of the resultant signal provides an indication of the angle a, as indicated by the relationship shown in Equation 5, and the amplitude of the resultant signal determines the value of the angle 7, as indicated by Equation 8. The angle a determines the amount of roll that the amount gimbal 28 should experience at any instant to maintain theantenna 16 pointed at a target, and the angle 7 indicates the pivotal movement that the ring gimbal 30 should experience.

The values of tan A and tan'E are derived from the signals produced by the alternator 56 (FIGURE 10). As previously disclosed, the alternator 56 rotates with the motor 54 at a substantially constant speed and produces a pair of signals having substantially a quadrature phase with each other. One of the signals has its impedance reduced, by the amplifier 132 and is then converted by the potentiometer 136 into an angular value representing tan A. The conversion takes place because the potentiometer 136 is ganged to the antenna in the interceptor 12, so that it rotates with the interceptor antenna through the angle A in the plane of azimuth. Similarly, the second signal from the alternator 56 is converted into a signal representing tan E, since the potentiometer 138 is pivoted with the interceptor antenna through the angle E.

The signals from the potentiometers 136 and 13 8 are then added vectorially by the. circuit 140 to produce a resultant signal having a phase and amplitude represented by tan A+j tan E. The peak amplitude of the signal produced by the circuit 140 is clipped by the amplifier 142, and the clipped signal is introduced to the detector 144 for comparison of its phase with the phase of a si nal produced by the resolver 130.

The resolver 130 produces a signal having an amplitude and phase given by the relationship sin a+ j cos a. This relationship is produced because the resolver 130 receives the quadrature signals produced by the alternator 56 and rotates these quadrature signals through an angle on indicative of the relative pivotal movement between the mount gimbal 28 and the missile. The rotation of the quadrature signals through the angle occurs because of the ganged relationship between the resolver 130 and the mount gimbal 28. At the same time that the resolver 130 changes the phase of the signals by the. angle a, it converts them into signals having vmues dependent upon the sin and cos of the angle a.

The phases of the signals from the adding circuit 140 and the resolver 130' are compared in the detector 144. If any difference occurs in the phases of the two signals, a resultant signal is produced, and this signal is difierentiated and then introduced through the switching circuit 150 to the motor 34. When the angle a through which the mount gimbal 28 has rotated is less than that required at any instant, the detector 144 produces a positive signal which acts upon the switching circuit 150 in such a direction that the motor 34 rotates the mount gimbal 28 to increase the angle a. This rotation occurs until the phase of the signal sin n+1 cos on corresponds to the phase of the signal tan A+j tan E. Similarly, the detector produces a negative signal when on is greater than that required to point the antenna 16 at any instant at the target, and this negative signal produces a rotation of the motor 34 and the mount gimbal 28 in a direction to reduce the angle a. The error signal from the detector 144 is first differentiated before being introduced to the motor 34 so that the motor will be operated at a greater speed when the error is increasing relatively fast than when it is increasing slowly. ln this way, the differentiator anticipates any error that may occur and imparts an increased sensitivity and stability to the system.

Since the mount gimbal 28 is rotated by the motor 3a to give the signal fro-m the resolver 13% the same phase as the signal from the summing. circuit 149, the signal from the resolver 130 can be used as a reference signal to determine the amount of rotation required of the antenna 16 on the ring gimbal St). The signal from the resolver 13% can also serve as a reference signal because the vectorial addition of the sine and cosine functions of the same angle causes the amplitude of the signal to be always substantially unity. This reference signal is amplified and then resolved by the potentiometer 164 through the tangent of an angle 0 corresponding to the movement at any instant of the antenna 16 in the plane of the ring gimbal 30.

The amplitude of the signal representing tan 7 is compared in the subtracting circuit 154 with the amplitude of the signal representing tan 6, and any difference in amplitude is detected and utilized by the motor 162 to drive the potentiometer 164 in a direction to reduce the amplitude difference. The motor also drives the synchro 168 -ciples involved are susceptible of numerous other appli- 10 through the same angle as the potentiometer 164 and causes the synchro to produce a signal having an amplitude dependent upon its angular movement. As previously disclosed, the synchro 163 is housed in the interceptor.

The amplitude of the signal from the synchro 168 is compared with the amplitude of the signal from the synchro 175, which is housed in the missile antenna 16, and any difference in the amplitudes of the two signals is determined by the subtracting circuit 170. After being amplified and detected, the difference signal is applied through the relay circuit 182 to the motor 178. If the signal is negative, the motor 178 drives the synchro 38 through the gear train 18!) and the ring gimbal 30 in a direction to increase the angular displacement of the synchro 38. Similarly, the displacement of the synchro 38 is reduced when a positive error signal is produced in the subtracting circuit 179. In this way, the synchro 38 follows the movement of the synchro 168, which in turn moves in accordance with the amplitude of the signal from the summing circuit 140. At the same time that .the motor 178 causes a movement of the synchro 3 8, it also causes a movement of the ring gimbal 30 so as to of azimuth and elevation into corresponding movements of the missile antenna on its mount and ring gimbals.

Although this invention has been disclosed and illustrated with reference to particular aplications, the princations which will be apparent to persons skilled in the art. The invention is therefore, to be limited only as indicated by the scope of the appended claims.

What is claimed is:

1. In combination in an interceptor for launching a missile to intercept a target, a radar system, an antenna in the radar system adapted to be positioned in accordance with the position of the target relative to the interceptor, imeans associated with the radar antenna and operative 'before the release of the missile to produce a control signal having a phase and amplitude dependent upon the position of the antenna, an antenna in the missile pivotable relative to the missile, and means for producing a movement of the missile antenna relative to the missile in accordance with the phase and amplitude of the control signal so as to point the antenna at the target.

2. In combination in an interceptor for launching a missile to intercept a target, a radar system, an antenna in the radar system adapted to be pivoted before the release or the missile in accordance with the position of :the target relative to the interceptor, means for converting the angular movement of the radar antenna into a control signal having a phase and amplitude indicative of the antenna movement in a pair of predetermined polar planes, an antenna in the missile p-ivotable in the polar planes relative to the missile, and means for producing a movement of the missile antenna in the polar planes relative to t 1e missile in accordance with the phase and amplitude of the control signal so as to point the antenna at the target.

3. In combination in an interceptor for launching a missile to intercept a target, a radar system, an antenna in the radar system adapted to be pivoted before the release of the missile in accordance with the position of the target relative to the interceptor, means for converting the angular movement of the radar antenna into a control signal having a phase and amplitude indicative of the antenna movement in a pair of predetermined polar planes, an antenna inthe missile pivotable in the polar the target.

planes relative to the missile, means for producing a comparison signal having a phase and amplitude dependent upon the movement of the missile antenna relative to the missile in the predetermined polar planes, and means for adjusting the position of the missile antenna relative to the missile in the polar planes in accordance with any differences in the phase of the control and compariscn signals and the amplitudes of these signals.

4. In combination in an interceptor for launching a missile to intercept a target, a radar system, an antenna in the radar system adapted to be positioned in accordance with the position of the target relative to the interceptor, means for converting the angular movement of the radar antenna into a control signal having a phase indicative of the antenna movement in a predetermined polar plane and an amplitude indicative of the antenna movement in a second polar plane substantially perpendicular to the first plane, an antenna in the missile pivotable relative to the missile, means for producing a comparison signal having a phase dependent upon the movemen-t of the missile antenna relative to the missile in the first polar plane and an amplitude dependent upon the movement of the antenna relative to the missile in the second plane, means for adjusting the position of the missile antenna relative to the missile in the first polar plane in accordance with any difference between the phases of the control and comparison signals, and means for adjusting the position of the missile antenna relative to the missile in the second polar plane in accord- ,ance with any difierence between the amplitudes of the control and comparison signals.

5. In combination in an interceptor for launching a missile to intercept a target, a missile antenna pivotable relative to the missile, an antenna housed in the inter- 6. In combination in an interceptor for launching a missile to intercept a target, a missile antenna, an antenna housed in the interceptor, means operative before the release of the missile to pivot the interceptor antenna in a first pair of substantially perpendicular planes to maintain the antenna pointed at the target, means for producing a control signal having a phase and amplitude dependent upon the movement of the interceptor antenna in the first pair of planes, means for producing a comparison signal having a phase and amplitude dependent upon the movement of the missile antenna in a second pair of substantially perpendicular planes, the secondpair of planes having an angular relationship to the first pair of planes dependent upon prior movements of the missile antenna in the second pair of planes, and means operative in accordance with any differences between the control and comparison signals to adjust the position of the missile antenna in the second pair of planes so as to maintain the antenna pointed at the target.

7. In combination in an'interceptor for launching a missile to intercept a target, an antenna housed in the interceptor, means for transmitting pulses towards the target and for receiving pulses from the target, means operative in accordance with the received pulses to pivot the interceptor antenna before the release of the missile in a first pair of substantially perpendicular planes to maintain the antenna pointed at the target, means for producing a control signal having characteristics dependent upon the pivotal movement of the interceptor antenna in the first pair of planes, a missile antenna pivotable in 'a second pair of substantially perpendicular planes, and means operative by the control signal to pivot the missile antenna in the second pair of planes to maintain the antenna pointed at the target.

8. In combination in an interceptor for launching a missile to intercept a target, an antenna housed in the interceptor, means operative before the release of the missile to pivot the interceptor antenna angularly in a first pair of substantially perpendicular planes to maintain the antenna facing the target, means for converting the movement of the interceptor antenna in one of the planes into a first signal having an amplitude dependent upon a predetermined trigonometric function of the angular movement, means for converting the movement of the interceptor antenna in the other 'plane into asecond signal having a quadrature phase relative to the first signal and an amplitude dependent upon a predetermined trigonometric function of the angular movement, means for combining the first and second signals to produce a control signal, an antenna in the missile, and means operative in accordance with the control signal to pivot the missile antenna in a second pair of substantially perpendicular planes having an angular relationship to the first pair of planes dependent upon previous movements of the antenna.

9. In combination in an interceptor for launching a missile to intercept a target, an antenna housed in the interceptor, means operative before the release of the missile to pivot the interceptor antenna angularly in a first pair of substantially perpendicular planes to maintain the antenna pointed at the target, means for converting the movement of the interceptor antenna in one of the planes into a first signal having an amplitude dependent upon a predetermined trigonometric relationship of the angular movements in the first pair of planes, means for converting the movement of the interceptor antenna in the other plane into a second signal having a quadrature phase relative to the first signal and an amplitude dependent upon a predetermined trigonometric relationship of the angular movements in the first pair of planes, means for combining the first and second signals to produce a control signal, an antenna in the missile, and means operative in accordance with the amplitude and phase of the control signal to pivot the missile antenna in a second pair of planes having an angular relationship to the first pair of planes dependent upon prior movements of the missile antenna in the second pair of planes.

10. The combination in an interceptor for launching a missile to intercept a target, a missile antenna, an antenna housed in the interceptor, means operative before the release of the missile to pivot the interceptor antenna in a first pair of substantially perpendicular planes to maintain the antenna pointed at the target, means for converting the angular movements of the interceptor antenna in the first pair of planes into control signals having characteristics dependent upon predetermined trigonometric functions of the angular movements, means operative to produce a comparison signal having a phase and amplitude dependent upon prior movements of the missile an tenna in second and third .planes having a relationship to the first pair of planes dependent upon the movements of the antenna, means for pivoting the missile antenna in the second plane to minimize any difference between the phases of the control and comparison signals, and means for pivoting the missile antenna in the third plane to minimize any dilierence between the amplitudes of the control and comparison signals.

11. In combination in an interceptor for launching a missile to intercept to target, an antenna housed in the interceptor, means operative before the release of the missile to pivot the interceptor antenna angularly in a pair of substantially perpendicular planes to maintain the antenna pointed at the target, means for converting the movement of the interceptor antenna in one of the planes into a first signal having an amplitude dependent upon a predetermined trigonometric relationship of the angular ment of the interceptor antenna in the other plane into a second signal having a quadrature phase relative to the first signal and an amplitude dependent upon a predetermined trigonometric relationship of the angular movement in the plane, means for combining the first and second signals to produce a control signal, an antenna in the missile and having a plurality of gimbals for providing during flight of the missile pivotal movements of the missile about the axes of the gimbals, means operative before the release of the missile to pivot the missile antenna about the axis of one of the gimbals in the plurality in accordance wtih the phase of the control signal to maintain the missile antenna pointed at the target, and means operative before the release of the missile to pivot the missile antenna about the axis of another of the gimbals in the plurality in accordance with the amplitude of the control signal to maintain the antenna pointed at the target.

12. In combination in an interceptor for launching a missile to intercept a target, an antenna in the missile and having a plurality of gimbals for providing a pivotal movement of the missile during its flight about the axes of the gimbals, the axes of the gimbals being substantially perpendicular to one another, an antenna housed in the interceptor, means operative before the release of the missile to pivot the interceptor antenna in a pair of substantially perpendicular planes to maintain the antenna pointed at the target, means for converting the angular movements of the interceptor antenna in one of the planes in the pair to produce a first signal having an amplitude dependent upon the angular movement in the plane, means for converting the angular movements of the interceptor antenna in the other plane in the pair to produce a second signal having an amplitude dependent upon the angular movement in the plane, means for combining the first and second signals to produce a control signal, means operative to produce a comparison signal having a phase and amplitude dependent upon prior movements of the missile antenna about the axes of first and second gimbals in the plurality, means for pivoting the missile antenna about the axis of the first gimbal in the plurality to minimize any difference between the phases of the control and comparison signals and to maintain the missile antenna pointed at the target, and means for pivoting the missile antenna about the axis of another of the gimbals in the plurality to minimize any differences between the amplitudes of the control and comparison signals and to maintain the antenna pointed at the target.

13. In combination in an interceptor for launching a missile to intercept a target, an antenna in the missile, a first gimbal in the antenna for providing a pivotal movement of the antenna relative to the missile in a first plane, a second gimbalmounted on the first gimbal to provide a pivotal movement of the antenna relative to the missile in a second plane substantially perpendicular to the first plane, an antenna housed in the interceptor, means operative before the release of the missile to pivot the interceptor antenna in a pair of substantially perpendicular planes to maintain the antenna pointed at the target, electrical circuits for converting the angular movements of the interceptor antenna in the pair of planes into a control signal having a phase and amplitude dependent upon the angular movements of the interceptor antenna in the pair of planes, electrical circuits for producing a first comparison signal having characteristics dependent upon the movement of the antenna on the first gimbal before the release of the missile, means for providing a movement of the antenna on the first gimbal to minimize any differences between the first comparison signal and the phase of the control signal, electrical circuits for producing a second comparison signal having characteristics dependent upon the movement of the antenna on the second gimbal before the release of the missile, and means for providing a movement of the antenna on the second gimbal to minimize any differences between the 14 second comparison signal and the amplitude of the control signal.

14. In combination in an interceptor for launching a missile to intercept a target, an antenna in the missile, a first gimbal in the antenna for providing a pivotal movement of the antenna relative to the missile in a first plane, a second gimbal mounted on the first gimbal to provide a pivotal movement of the antenna relative to the missile in a second plane substantially perpendicular to the first plane, an antenna housed in the interceptor, means operative before the release of the missile to pivot the interceptor antenna in a pair of substantially perpendicular planes to maintain the antenna pointed at the target, electrical circuits for converting the angular movements of the interceptor antenna in the pair of planes into a control signal having a phase dependent upon the relative angular movements of the interceptor antenna in the pair of planes and having an amplitude dependent upon the vectorial magnitudes of the angular movements in the pair of planes, electrical circuits including signal resolvers for producing a first comparison signal having characteristics dependent upon the movement of the antenna on the first gimbal, electrical circuits for providing a movement of the antenna on the first gimbal to minmize any differences between the first comparison signal and the phase of the control signal, electrical circuits including signal resolvers for producing a second comparison signal having characteristics dependent upon the movement of the antenna on the second gimbal before the release of the missile, and means for providing a movement of the antenna on the second gimbal to minimize any differences between the second comparison signal and the amplitude of the control signal.

15. In combination in an interceptor for launching a missile to intercept a tar-get, an antenna in the missile, a first gimbal in the antenna for providing a pivtol movement of the antenna relative to the missile in a first plane, a second gimbal mounted on the first gimbal to provide a piovtal movement of the antenna relative to the missile in a second plane substantially perpendicular to the first plane, an antenna housed in the interceptor, means operative before the release of the missile to pivot the interceptor antenna in a pair of substantially perpendicular planes to maintain the antenna pointed at the target, electrical circuits including a summing circuit for converting the angular movements of the interceptor antenna in the pair of planes into a control signal having a phase dependent upon the relative angular movements of the interceptor antenna in the pair of planes and having an amplitude dependent upon the vectorial magnitudes of the angular movements in the pair of planes, electrical circuits including a signal resolver for producing a first comparison signal having characteristics dependent upon the movement of the antenna on the first gimbal, electrical circuits including a detector for producing a first signal representing any difference between the first comparison signal and the phase of the control signal, means including a motor and a synchro for producing a movement of the antenna on the first gimbal to minimize the first difference signal, electrical circuits for producing a second comparison signal having characteristics dependent upon the movement of the antenna on the second gimbal, electrical circuits including a subtracting circuit and a detector for producing a second signal representing any difference between the second comparison signal and the amplitude of the control signal, and means including a motor and a synchro for producing a movement of the antenna on the second gimbal to minimize the second second difference signal.

References Cited in the file of this patent UNITED STATES PATENTS 2,448,007 Ayres Aug. 31, 1948 2,512,693 Sparks et al. June 27, 1950 2,557,401 Agins et al. June 19, 1951 

11. IN COMBINATION IN AN INTERCEPTOR FOR LAUNCHING A MISSILE TO INTERCEPT TO TARGET, AN ANTENNA HOUSED IN THE INTERCEPTOR, MEANS OPERATIVE BEFORE THE RELEASE OF THE MISSILE TO PIVOT THE INTERCEPTOR ANTENNA ANGULARLY IN A PAIR OF SUBSTANTIALLY PERPENDICULAR PLANES TO MAINTAIN THE ANTENNA POINTED AT THE TARGET, MEANS FOR CONVERTING THE MOVEMENT OF THE INTERCEPTOR ANTENNA IN ONE OF THE PLANES INTO A FIRST SIGNAL HAVING AN AMPLITUDE DEPENDENT UPON A PREDETERMINED TRIGONOMETRIC RELATIONSHIP OF THE ANGULAR MOVEMENT IN THE PLANE, MEANS FOR CONVERTING THE MOVEMENT OF THE INTERCEPTOR ANTENNA IN THE OTHER PLANE INTO A SECOND SIGNAL HAVING A QUADRATURE PHASE RELATIVE TO THE FIRST SIGNAL AND AN AMPLITUDE DEPENDENT UPON A PREDETERMINED TRIGONOMETRIC RELATIONSHIP OF THE ANGULAR MOVEMENT IN THE PLANE, MEANS FOR COMBINING THE FIRST AND SECOND SIGNALS TO PRODUCE A CONTROL SIGNAL, AN ANTENNA IN THE MISSILE AND HAVING A PLURALITY OF GIMBALS FOR PROVIDING DURING FLIGHT OF THE MISSILE PIVOTAL MOVEMENTS OF THE MISSILE ABOUT THE AXES OF THE GIMBALS, MEANS OPERATIVE BEFORE THE RELEASE OF THE MISSILE TO PIVOT THE MISSILE ANTENNA ABOUT THE AXIS OF ONE OF THE GIMBALS IN THE PLURALITY IN ACCORDANCE WTIH THE PHASE OF THE CONTROL SIGNAL TO MAINTAIN THE MISSILE ANTENNA POINTED AT THE TARGET, AND MEANS OPERATIVE BEFORE THE RELEASE OF THE MISSILE TO PIVOT THE MISSILE ANTENNA ABOUT THE AXIS OF ANOTHER OF THE GIMBALS IN THE PLURALITY IN ACCORDANCE WITH THE AMPLITUDE OF THE CONTROL SIGNAL TO MAINTAIN THE ANTENNA POINTED AT THE TARGET. 